Three-dimensional (3D) or stereoscopic images have been widely used in video gaming, virtual reality systems, and other 3D display systems. 3D viewing glasses are typically used as the simplest and most convenient mode for users to view 3D images. In general, they use shutter lenses so that the viewer's eyes alternately see left and right-eye image views that are perceived in the brain as a 3D image. For example, 3D Viewing Technologies, Inc., of Miami, Fla., provides the Virtual FX™ System which receives an ordinary video signal from a DVD, video player, cable box or game console, and converts it to a 3D video signal (i.e. superimposed left and right image views) that is displayed on the TV set. The image conversion is performed by standard mathematical algorithms which calculate separate and distinct left-eye and right-eye images displayed on the TV screen in an alternating format. A pair of 3D shutter glasses is used which receive an infrared signal transmitted from the converter box to render the left and right lenses alternately transparent and opaque in sync with the TV displayed image so that the right image is seen by the right eye, and the left image by the left eye, thus producing a stereographic 3D image. There are several lensing methods for blocking/passing views to the human eye, for example, double layer crossed polarized lenses or electronically controlled polarization shutter lenses.
The control information for 3D shutter lenses is synchronized with the display, usually by using the sync signal of the display. The sync signal is an ordered sequence of pairs, rather than a stream of identical signals. In other systems, it may be an ordered sequence of quad signals, with 2 successive sync pulses, for the 2 fields of a single video frame, keeping the same eye viewing. Advanced computer systems, particularly from Sun Microsystems and Silicon Graphics have used this form of stereo capability.
The computational methods for generating right and left stereoscopic images from given image data are well known, for example, as described in “3d Stereo Rendering Using OpenGL (and GLUT), by Paul Bourke, November 1999, available at the Internet page addressed as http://astronomy.swin.edu.au/pbourke/opengl/stereogl/. The method of determining the right and left eye offset and computing corresponding left and right eye images has become a standard in the industry.
Some popular 3D video games are created with 3D vision capability a common Application Programming Interface (API) for handling the 3D rendering and display functions of the game. The API drivers generate right and left stereoscopic image outputs to right and left stereoscopic display cards that generate the resulting 3D stereoscopic display “Stereo vision” is obtained by delivering appropriate right and left offset images to the user's right and left eyes through a suitable 3D shutter glasses, 3D display, VR goggles, or “no glasses required” 3D monitor. Examples of common API formats used for PC games include Glide™, developed by 3dfx Interactive, Inc., of Alviso, Calif., OpenGL™, developed by Silicon Graphics, Inc., of Mountain View, Calif., and DirectX™, distributed by Microsoft Corp., of Redmond, Wash.
The prior 3D viewing systems using viewing glasses have had the problem that a specialized piece of equipment, the converter/synchronization box, is required to sync with the display image and transmit the glasses sync control information to the viewing glasses. It is deemed desirable to eliminate this extra piece of equipment and have the viewing glasses handle control of alternate left and right-eye image viewing. This would allow the viewing glasses to be used for all similar images sources, rather than having a special converter/synchronization box for each type of images source.